Scientific Intelligence — Geology. 179 



with ihe subjacent secondary formations ; 2. The tertiary for- 

 mations are the only ones containing fossil remains of species 

 which live at the present day ; 3. The analogous species are 

 more numerous in proportion as the formation is more modem, 

 and reciprocally ; 4. Constant proportions (Sin 100, 19 in 100, 

 52 in 100), in the number of analogous species, determine the 

 age of the tertiary formations ; 5. The tertiary formations are 

 in superposition, and not in parallelism, as was at first suppo- 

 sed ; 6. The tertiary formations ought, according to their zoo- 

 logical characters, to be divided into three groups. We shall 

 now give the conclusions relative to the temperature of the three 

 series of tertiary strata at the epoch of their formation. The 

 most superficial tertiary formations were deposited when the tem- 

 perature of Europe was nearly similar to what it is at present. 

 The proofs are the following : — The tertiary formations of this 

 age in Norway, Sweden, Denmark, St Hospice near Nice, and of 

 a part of Sicily, contain, in a fossil state, all the identical species 

 of the corresponding seas. These same formations of the Me- 

 diterranean side of France, of Spain and Piedmont, of Italy, of 

 Sicily, of the Morea, and pf Barbary (Algiers) contain a great por- 

 tion of the species which live in the Mediterranean, but contain 

 also some whose analogues no longer exist, or are distributed in 

 small quantity in the hot regions of the Atlantic Ocean and in 

 the Indian Seas. These observations have induced me to be- 

 lieve that the Mediterranean has experienced a slight depression 

 of temperature, since the chain of the Atlas on the one side, and 

 that of the Apennines on the other, assumed their present relief. 

 During the second tertiary epoch, to which belong a great num- 

 ber of small basins, scattered especially near the centre of Europe, 

 the temperature has been very different from that which at pre- 

 sent exists in these places. In fact, the species peculiar to 

 the Senegal and the sea of Guinea, those which best represent 

 the temperature of that part of the equatorial zone, are found 

 in the fossil state in the beds of this second period. The tem- 

 perature of the third period, at first a little more elevated than 

 our own in the Mediterranean basin, has become similar to that 

 which we experience ; in the north the species of the north are 

 fossil ; in the south the species of the south. Thus, since the 

 commencement of the tertiary formations, the temperature has 

 been constantly diminishing, passing in our climates from the 



